1. Field of the Invention
The present invention relates to lasers and, more particularly, to a solid state laser array and the method of fabricating such an array.
2. Prior Art
In an electrically pumped multi-heterojunction laser, the radiation usually exits in a direction parallel to the junctions. In a single laser, this offers no problems. However, when a multiplicity of lasers is to be deployed in a matrix array on a common substrate, the direction of radiation places restrictions upon the fabricating techniques.
One patentee, M. Borner, sought to solve this problem in U.S. Pat. No. 3,614,661 by deploying a plurality of individual lasers on a common substrate with the plane of the laser junctions perpendicular to the plane of the substrate. It is to be noted that the active layers in the lasers all lie in different planes and cannot therefore be deposited in common upon the substrate.
In the instant invention, the junctions for all of the lasers in the array lie in the same plane. Therefore, the various laminae constituting the lasers may be deposited in common upon the substrate. This allows for economical mass fabrication techniques using solid state device deposition techniques. Separation of the individual lasers by preferential etching provides not only the requisite resonant cavity geometry, but also the requisite isolation of the lasers. A periodic grating whose plane is parallel to the junctions induces a leaky coupling of the radiation out of each laser in a direction perpendicular to the plane of the array.